Optima YELLOWTOP D27F Ultra high-performance Spiralcell Technology AGM (absorbent glass mat) dual-purpose (deep-cycle and starting) battery. This batteries have three times the cycling capability (recharge ability) with ultimate cranking power for your car or truck to outperform traditional batteries. Perfect for powering heavy electrical loads, including winches, audio systems, inverters, and other demanding vehicle accessories and electronics. Lower internal resistance provides more efficient power output and faster recharges. Cold cranking amps: 830, Cranking amps: 1025, Nominal voltage: 12 Volt, Open circuit voltage (fully charged): 13.1 Volt, Internal resistance (fully charged): 0.0025, Capacity: 66 Ampere hour, Reserve capacity: BCI: 140 minutes (25 Ampere discharge, 80 Degree Fahrenheit (26.7 Degree Celsius), to 10.5 Volts cut-off).Case Material - Polypropylene.